Coronavirus has broken out on the UK's second aircraft carrier, HMS Prince of Wales, meaning that both of the Royal Navy's largest vessels have COVID cases on board.
About eight crew members on the Prince of Wales tested positive after going ashore in Gibraltar, Sky News understands. This development was first reported by The Sun newspaper.
On Tuesday, a much larger outbreak was revealed on Britain's flagship carrier, HMS Queen Elizabeth and the fleet of escorting warships.
Ben Wallace, the defence secretary, said the outbreak was "inevitable" for a group of vessels on a global, months-long voyage.
He told Sky News that rules about sailors going ashore at different ports are being reviewed in a sign that they may have to be tightened to reduce the risk of crew members picking up the disease and bringing it back to the carrier strike group.
"The good news is no one has so far has in any way even been referred to sick bay," Mr Wallace said during a visit to the United States.
"It means we are going to handle it but of course we are going to review every time we stop.
"We will make sure we check, make sure there is a risk assessment done and if necessary either people won't go ashore or indeed if the host nation doesn't want people to come aboard we will respect that," he added.
More than 100 crew members on HMS Queen Elizabeth have tested positive for coronavirus, with cases also on four other Royal Navy ships in the carrier group.
Mr Wallace said the rate of new infections was slowing and said the strike group's maiden voyage, which will include a transit through the South China Sea, is being kept under review.
"We have got days and days of crossing the Indian Ocean before these ships even come to port. We have got lots of time to make decisions if we need to," he said.
"It is inevitable at some stage in these eight-nine months of deployment that somebody would contract coronavirus…To expect it not to happen would actually be far more deluded."
Away from the carrier strike group, HMS Prince of Wales was due to return as planned to Portsmouth on Thursday at the end of the ship's final sea trial before becoming operational.
All crew members are double vaccinated.
The infected sailors will stay aboard to complete their isolation period but everyone else will be allowed to disembark following PCR tests.